This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Phosphoribose epimerases produce key intermediates for the synthesis of the unique bacterial cell wall of mycobacteria. Because of their unique function in this group of bacteria, they represent attractive targets for the development of new drugs against Mycobacterium tuberculosis. However, there are no protein structures currently available to aid in this effort to develop new small molecule inhibitors against these enzymes.We have recently been able to obtain diffracting crystals for one such phosphoribose epimerase. Preliminary X-ray diffraction experiments show that a structure solution using selenomethionine derivatives will be feasible as soon as higher resolution data can be collected.